Mixing device



J. H. WITTMANN MIXING DEVICE March 31, 1942.

Filed Oct. 11, 1940 INVENTOR ATTOHN EY Patented Mar. 31, 1942 UNITED STATES PATENT OFFICE Application October 11, 1940, Serial No. 360,759

Claims.

This invention relates to mixing devices, particularly adapted for whipping cream, mixing liquids, or mixing liquids with various ingredients, and has for its principal object to provide a device of this character with flexible mixing elements that remain alive and active so as to scrape up every particle of settling ingredients and thereby provide an exceptionally effective and eflicient mixer.

Other objects of the invention are to provide a simple and inexpensive construction capable of easy manufacture and assembly; to provide a mixer that is self-cleaning and extremely sanitary; to provide flexible mixing elements consisting of a plurality of convolutions designed to avoid interlock of one convolution into another; and to provide a mixer with agitating elements that are self-adjustable relatively to the bottom of a container so that the elements operate in close contact therewith.

In accomplishing these and other objects of th invention, as hereinafter pointed out, I have provided improved details of structure, the preferred forms of which are illustrated in the accompanying drawing, wherein:

Fig. l is a perspective view of a mixing device constructed in accordance with the present invention and showing contact of the mixing elements with the bottom of a mixing bowl.

Fig. 2 is a detail perspective view of the flex--; ible mixing elements with the hooked ends thereof brought together and ready to be connected with the operating shaft.

Fig. 3 is a perspective view of one of the mixing elements in relaxed condition showing the form v of the convolutions.

Fig. 4 is a detail sectional view through the handle, particularly illustrating the nut-like bearing for engaging the spiral section of the operating shaft. o Fig. 5 is a'detail perspective view of the lower portion of the handle, nut-like bearing, upper portion of the operating shaft, and the bearing retaining caps, in disassembled spaced relation.

Referring more in detail to the drawing:

l designates a mixing device constructed in accordance with the present invention andwhich includes an operating shaft 2, mixing or agitating elements 3 and 4, and a handle 5.

The operating shaft includes a relatively rigid, rcd-like body 6 terminating at the lower end in a flattened head 1 forming lateral wings 8 and 9 having spaced apertures I0 and II therein. The lower portions of the wings terminate in a ballshaped step-bearing I2 on which the shaft is adapted for rotary support by the bottom of a mixing vessel. The upper portion of the shaft is shaped to provide a fiat, spiral thread l3, to engage in a slot-like opening 14 of a nut-like bearing disk 15. Above the spiral thread It the a pintle 18 above the collar.

shaft has a collar-like washer l6 supported on ears I! struck from the metal of the shaft, leaving The handle 5 has a shank l9 provided with an axial bore 20 in which is inserted a metallic tube 2! forming a housing for a coil spring 22, one end of which seats against the bottom 23 of the bore 20 and its opposite end engages over the pintle l8 and seats against the washer-like collar l-6 of the shaft when the shaft is inserted in the handle.

The washer-lik bearing I5 is retained in abutting relation with the tube by a cap 24 having a socket 25 of suitable diameter to snugly receive the part l5 and to engageover the shank of the handle, as clearly shown in Fig. 4, the cap being secured tothe shank by any suitable means such ,as a plastic cement.

The upper portion of the handle is in the form of a knob 26 adapted to be engaged by the fingers or palm of the hand to exert a downward pressure on the handle whereby the bearing l5 moves over the convolutions of the spiral thread to effect rotation of the shaft on the ball-like step-bearing l2, as later described. 1

The mixing or agitating elements 3 and 4 are formed of a flexible wire-like material of resilient character and wound into helical form to provide a plurality of convolutions 2'! increasing in diameter from one end toward the center convolution and then decreasing toward the other end to form a substantially barrel-shape when the formed element is in relaxed condition as shown in Fig. 3. The endmost convolutions terminate in hooks 28 and 29 to engage in the apertures l0 and I I. To engage the hooks in the apertures, the hooked ends are brought together to impart a curve in the axis of the helix, whereby the convolution at one end is adapted to extend substantially horizontally relative to the shaft while the convolution at the opposite end extends substantially parallel with the shaft as shown in Figs. 1 and 2. The convolutions are thus placed in compression on the attached sides and bulge outwardly on the, other to provide extended contact with the material to be mixed.

' When the mixing elements are attached to the 'heaol of the shaft, the intermediate convolutions are free to flex independently of each other, and the endmost convolutions hinge within the apertures l0 and I I so that the elements automaticalscrape on the bottom of the mixing vessel.

In using the mixing device, it is inserted within the mixing bowl so that the step-bearing l2 ments are gyrated therewith. The centrifugal.

force and the flexible, spring-like character of the convolutions automatically retain the mixing elements in scraping contact with the bottom of the bowl so that settling particles are scraped from the bottom and mixed with the liquid. Upon release of pressure on the handle, the spring returns the handle to its original position, and the nut-like bearing rotates the shaft in the opposite direction. Thus'by providing a reciprocating action to the handle, the agitating elements gyrate first in one direction and then in the other direction, the-number of rotations between changes in direction depending upon the stroke of the handle and the number of convo lutions in thespiral;

The mixing elements being formed of relatively thin material, remain alive and active during the entire operation thereof to thoroughly scrape up the particles and effect a quick and easy mixture of the materials.

Attention is directed to the fact that the tension produced incidental to common anchorage of the ends of the helix retains the convolutions in extended position and at varying angles with respect to the bottom of the vessel so that the angle of attack for each convolution is different and effects thorough agitation of the material so that unmixed or unwhipped liquid is not left in the bottom of the bowl.

The'flexible character of the agitating or mixing elements permits folding thereof against the, side of the shaft so that the entire device is readily packaged in a relatively small tube-like container (not shown). Upon release from the container, the convolutions readily return to their normal position as shown in Fig. 1.

From the foregoing it is obvious that I have provided a mixing device that is of simple, inexpensive construction and which is well adapted for mixing various ingredients with liquids or for whipping cream, beating eggs, and otherwise acting upon similar material.

What I claim and desire to secure by Letters Patent is:

positioned to act in planes substantially parallel with the axis of said shaft when the ends are secured to the wings, said intermediate convolutions of the elements being free and unattached and located in different radial planes substantially extending through axes of the pivotal connections.

2. A mixing device including, a rotatable shaft having an end for engaging the bottom of a vessel and provided with laterally extending-wings provided with openings therethrough, and flexible agitating elements each including a helical wire-like form normally consisting of a series of coaxial convolutions with the terminals of the end convolutions provided with hooks brought together and pivotally engaged in said openings of the wings, one of said end convolutions of each element being arranged to gyrate in a transverse tially extending plane relatively to the axis of said shaft and the opposite end convolutions positioned to act in planes substantially parallel with the axis of said shaft when the hooks are engaged in said openings, said intermediate convolutions of the elements being free and unattached to said shaft and located in different radial planes substantially extending through the axes of said openings, said intermediate convolutions being of larger diameter than the end convolutions to provide variable gyrational range with respect to the axis of the shaft.

3. A mixing device including, a rotatable shaft having an end adapted to' engage'the bottom of a vessel, flexible agitating elements each including a helical wire-like form normally consisting of a series of coaxial convolutions with the terminals of the end convolutions brought together, and means pivotally connecting said terminal ends to said shaft adjacent said end, one of said end convolutions of each element being arranged in a transverse plane relatively to the axis of said shaft and adapted to sweep in parallel contact with the bottom of the vessel and the other end convolutions being positioned to act in planes substantially parallel with the axis of said shaft when said terminals are engaged by said pivotal connecting means, said intermediate convolutions of the elements being free and unattached and located indifferent radial planes substanthrou'gh said pivotal connections.

4. A mixing device including, a rotatable shaft having an end adapted to engage the bottom of a vessel and provided with a flattened portion above said end having spaced openings therein, and flexible agitating elements each including a helical wire-like form normally consisting of a series of coaxial convolutions with the terminals of the end convolutions provided with hooks brought together and pivotally engaged in said openings of the flattened portion, one of said end convolutions of each element being arranged in a transverse plane relatively to the axis of said shaft and adapted to sweep in parallel contact with the bottom of the vessel and the other end convolutions positioned to act in planes substantially parallel with the axis of said shaft when the hooks are engaged in said openings, said intermediate convolutions of the elements being free and unattached and located in different radial planes substantially extending through said openings;

5; A mixing device including, a rotatable shaft having one end adapted to engage the bottom of a container, flexible agitating elements each including a helical wire-like form comprising a series of convolutions with their centers arranged on arcs in a plane parallel with the axis of the shaft, and means pivotally connecting the endmost convolutions of each element to said shaft, said intermediate convolutions of the elements being free and unattached and located in different radial planes substantially extending through the axes of the pivotal connections.

JOSEPH H. WI'I'TMANN. 

